Field of the Invention
The present invention relates to a sheet conveyance apparatus that conveys sheets, and an image forming apparatus that includes the sheet conveyance apparatus.
Description of the Related Art
Some image forming apparatuses, such as printers, facsimiles, and copying machines, cause a sheet to pass through an image forming portion while conveying the sheet upward in a substantially vertical direction, and form an image on the front side of the sheet. In a case where images are formed on both sides of a sheet, the apparatuses cause a sheet to pass through the image forming portion, reverse the sheet, convey the sheet downward in the substantially vertical direction, and cause the sheet to pass through the image forming portion again to form an image on the back side of the sheet. In this configuration, a conveyance path through which the sheet is conveyed downward in the substantially vertical direction and a conveyance path through which the sheet is conveyed upward in the substantially vertical direction are connected via a curved conveyance path.
As disclosed in Japanese Patent No. 3582531, there is proposed an image forming apparatus having a reverse conveyance unit that can reverse sheets. In the image forming apparatus, when a sheet is jammed in a conveyance path, an operator opens the reverse conveyance unit for example, and removes the sheet jammed in the conveyance path. In the image forming apparatus, the reverse conveyance unit, which can be opened and closed, is pivotably supported by an apparatus body, and a first guide plate is pivotably supported on a frame of the reverse conveyance unit.
In addition, a second guide plate is pivotably supported on the apparatus body, on an inner side of the image forming apparatus with respect to the first guide plate when the reverse conveyance unit is closed. Between the second guide plate and the apparatus body, there is formed a main path through which a sheet is conveyed upward to an image forming portion. Between the frame of the reverse conveyance unit and the first guide plate, there is formed a reconveyance path through which a sheet is conveyed downward to form an image on the back side of the sheets by re-conveying the sheet.
In the image forming apparatus described in Japanese Patent No. 3582531, the main path is provided in the apparatus body and the reconveyance path is provided in the reverse conveyance unit. In this configuration, however, when a sheet is jammed in a curved conveyance path, and an operator tries to open the reverse conveyance unit, an opening operation of the reverse conveyance unit may be hampered by the jammed sheet, or otherwise the sheet may be torn, lowering maintainability or operability in removing the jammed sheet. In addition to this, there has been desired to ensure positioning accuracy of components defining the conveyance paths in a state where an openable portion such as the reverse conveyance unit is closed, and to ensure appropriate dimensions of the conveyance paths to stably convey the sheets.